Model reduction of fractional impedance spectra for time–frequency analysis of batteries, fuel cells, and supercapacitors

Joint time–frequency analysis is an emerging method for interpreting the underlying physics in fuel cells,batteries,and supercapacitors.To increase the reliability of time–frequency analysis,a theoretical correlation between frequency-domain stationary analysis and time-domain transient analysis is urgently required.The present work formularizes a thorough model reduction of fractional impedance spectra for electrochemical energy devices involving not only the model reduction from fractional-order models to integer-order models and from high-to low-order RC circuits but also insight into the evolution of the characteristic time constants during the whole reduction process.The following work has been carried out:(i)the model-reduction theory is addressed for typical Warburg elements and RC circuits based on the continued fraction expansion theory and the response error minimization technique,respectively;(ii)the order effect on the model reduction of typical Warburg elements is quantitatively evaluated by time–frequency analysis;(iii)the results of time–frequency analysis are confirmed to be useful to determine the reduction order in terms of the kinetic information needed to be captured;and(iv)the results of time–frequency analysis are validated for the model reduction of fractional impedance spectra for lithium-ion batteries,supercapacitors,and solid oxide fuel cells.In turn,the numerical validation has demonstrated the powerful function of the joint time–frequency analysis.The thorough model reduction of fractional impedance spectra addressed in the present work not only clarifies the relationship between time-domain transient analysis and frequency-domain stationary analysis but also enhances the reliability of the joint time–frequency analysis for electrochemical energy devices.

Charge adaptive phytochemical-based nanoparticles for eradication of methicillin-resistant staphylococcus aureus biofilms

The intrinsic resistance of MRSA coupled with biofilm antibiotic tolerance challenges the antibiotic treatment of MRSA biofilm infections.Phytochemical-based nanoplatform is a promising emerging approach for treatment of biofilm infection.However,their therapeutic efficacy was restricted by the low drug loading capacity and lack of selectivity.Herein,we constructed a surface charge adaptive phytochemical-based nanoparticle with high isoliquiritigenin(ISL)loading content for effective treatment of MRSA biofilm.A dimeric ISL prodrug(ISL-G2)bearing a lipase responsive ester bond was synthesized,and then encapsulated into the amphiphilic quaternized oligochitosan.The obtained ISL-G2loaded NPs possessed positively charged surface,which allowed cis-aconityl-D-tyrosine(CA-Tyr)binding via electrostatic interaction to obtain ISL-G2@TMDCOS-Tyr NPs.The NPs maintained their negatively charged surface,thus prolonging the blood circulation time.In response to low pH in the biofilms,the fast removal of CA-Tyr led to a shift in their surface charge from negative to positive,which enhanced the accumulation and penetration of NPs in the biofilms.Sequentially,the pH-triggered release of D-tyrosine dispersed the biofilm and lipase-triggered released of ISL effectively kill biofilm MRSA.An in vivo study was performed on a MRSA biofilm infected wound model.This phytochemical-based system led to~2log CFU(>99%)reduction of biofilm MRSA as compared to untreated wound(P<0.001)with negligible biotoxicity in mice.This phytochemical dimer nanoplatform shows great potential for long-term treatment of resistant bacterial infections.

Association between Exposure of Rare Earth Elements and Outcomes of In Vitro Fertilization-Embryo Transfer in Beijing

Objective The study aimed to investigate the impact of rare earth elements(REEs)exposure on pregnancy outcomes of in vitro fertilization-embryo transfer(IVF-ET)by analyzing samples from spouses.Methods A total of 141 couples were included.Blood and follicular fluid from the wives and semen plasma from the husbands,were analyzed for REEs using inductively coupled plasma mass spectrometry(ICP-MS).Spearman's correlation coefficients and the Mann–Whitney U test were used to assess correlations and compare REE concentrations among three types of samples,respectively.Logistic models were utilized to estimate the individual REE effect on IVF-ET outcomes,while BKMR and WQS models explored the mixture of REE interaction effects on IVF-ET outcomes.Results Higher La concentration in semen(median 0.089 ng/mL,P=0.03)was associated with a lower fertilization rate.However,this effect was not observed after artificial selection intervention through intracytoplasmic sperm injection(ICSI)(P=0.27).In semen,the REEs mixture did not exhibit any significant association with clinical pregnancy.Conclusion Our study revealed a potential association between high La exposure in semen and a decline in fertilization rate,but not clinical pregnancy rate.This is the first to report REEs concentrations in follicular fluid with La,Ce,Pr,and Nd found at significantly lower concentrations than in serum,suggesting that these four REEs may not accumulate in the female reproductive system.However,at the current exposure levels,mixed REEs exposure did not exhibit reproductive toxicity.

Exploring the Application of Refined Management in University Financial Management

The refined management of university finances primarily involves optimizing management methods and continuously improving financial management levels.This process helps enhance fund utilization efficiency,optimize resource allocation,ensure the rational use of educational funds,and provide solid financial support for the development of teaching,research,and other university undertakings.This paper explores the application of refined management in university financial management.

Measurement and prediction of isothermal vapor–liquid equilibrium of a-pinene+camphene/longifolene+abietic acid+palustric acid+neoabietic acid systems

The vapor–liquid equilibrium(VLE)data of a-pinene+camphene+[abietic acid+palustric acid+neoabietic acid]and a-pinene+longifolene+[abietic acid+palustric acid+neoabietic acid]systems at 313.15 K,333.15 K and 358.15 K were measured by headspace gas chromatography(HSGC).These data was compared with the predictions value by conductor-like screening model for realistic solvation(COSMO-RS).Moreover,the calculated data of COSMO-RS and Non-Random Two-Liquids(NRTL)models showed good agreement with the experimental data.It was found that the three resin acids inhibited the volatility of a-pinene,camphene and longifolene and resulted in the decrease of total pressure.Moreover,HE(HB)contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of a-pinene,camphene and longifolene with the three resin acids.In addition,the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.

The Joule–Thomson effect of (CO_(2)+H_(2)) binary system relevant to gas switching reforming with carbon capture and storage(CCS)

The Joule-Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with carbon capture and storage(CCS). In this work, a set of apparatus was set up to determine the Joule-Thomson effect of binary mixtures(CO_(2)+ H_(2)). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule-Thomson coefficients(μ_(JT)) for(CO_(2)+ H_(2)) binary mixtures with mole fractions of carbon dioxide(x_(CO_(2))= 0.1, 0.26, 0.5,0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs(PR,SRK, PR, BWR and GERG-2008 equation) were used to calculate the μ_(JT)for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature.Moreover, the Joule-Thomson inversion curves(JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO_(2). The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.

A Shape-Memory Deployable Subsystem with a Large Folding Ratio in China’s Tianwen-1 Mars Exploration Mission

Once China’s Tianwen-1 Mars probe arrived in a Mars orbit after a seven-month flight in the deep cold space environment,it would be urgently necessary to monitor its state and the surrounding environment.To address this issue,we developed a flexible deployable subsystem based on shape memory polymer composites(SMPC-FDS)with a large folding ratio,which incorporates a camera and two temperature telemetry points for monitoring the local state of the Mars orbiter and the deep space environment.Here,we report on the development,testing,and successful application of the SMPC-FDS.Before reaching its Mars remote-sensing orbit,the SMPC-FDS is designed to be in a folded state with high stiffness;after reaching orbit,it is in a deployed state with a large envelope.The transition from the folded state to the deployed state is achieved by electrically heating the shape memory polymer composites(SMPCs);during this process,the camera on the SMPC-FDS can capture the local state of the orbiter from multiple angles.Moreover,temperature telemetry points on the SMPC-FDS provide feedback on the environment temperature and the temperature change of the SMPCs during the energization process.By simulating a Mars on-orbit space environment,the engineering reliability of the SMPC-FDS was comprehensively verified in terms of the material properties,structural dynamic performance,and thermal vacuum deployment feasibility.Since the launch of Tianwen-1 on 23 July 2020,scientific data on the temperature environment around Tianwen-1 has been successfully acquired from the telemetry points on the SMPCFDS,and the local state of the orbiter has been photographed in orbit,showing the national flag of China fixed on the orbiter.

Update of latest data for combined therapy for esophageal cancer using radiotherapy and immunotherapy:A focus on efficacy,safety,and biomarkers

Esophageal cancer usually has a poor prognosis.Given the significant breakthrough with tumor immunotherapy,an increasing number of clinical studies have demonstrated that the combination of radiotherapy and immune checkpoint inhibitors(ICIs)may have a synergistic effect and good outcome in esophageal cancer.Clinical studies of immunoradiotherapy(iRT)for esophageal cancer have proliferated enormously from 2021 to the present.However,a summary of the efficacy and toxicity of combined therapy to guide esophageal cancer treatment in clinical practice is lacking.For this review,we integrate the latest data to analyze and assess the efficacy and safety of iRT for esophageal cancer.In addition,we discuss better predictive biomarkers,therapeutic options for specific populations,and other challenges to identify directions for future research design.

丹酚酸B和人参皂苷Rg1合用对卒中后出血性转化的抑制作用

目的:对脑卒中患者进行血管再通治疗不仅受时间窗的限制,还伴随着出血性转化的风险。本研究在小鼠大脑中动脉阻塞(MCAO)模型上观察了丹酚酸B和人参皂苷Rg1合用(Salb/Rg1)对脑缺血时间窗和出血性转化的影响。方法:通过脑梗死体积、神经行为障碍和组织形态学检查评估SalB/Rg1的保护作用和时间窗。对MCAO小鼠进行葡萄糖刺激和再灌注考察SalB/Rg1对出血性转化的抑制。SalB/Rg1对出血性转化的抑制作用是通过免疫荧光染色和原位明胶酶谱技术来确定的。结果:通过组织病理学染色根据细胞结构进一步确定SalB/Rg1以剂量依赖的方式显著减少了梗塞体积并改善了神经行为,且SalB/Rg1对卒中的保护时间窗长达9h。其次,SalB/Rg1下调了出血评分、梗死体积并改善异常神经行为。最后,发现SalB/Rg1对出血性转化的抑制与它对神经血管单元完整性的保护相伴随。在梗死的边缘区域,SalB/Rg1减少了星形胶质细胞的激活,保持了内皮细胞之间连接蛋白(Claudin-5)的丰度,大大降低了基质金属肽酶9(MMP-9)的活性。结论:SalB/Rg1是一种很有前景的抗卒中,尤其是抗出血性转化的新策略。

Manual Uterine Fundal Pressure in the Spontaneous Delivery during the Second Stage of Labor: A Pilot Case-Control Study Following an Analysis of Questionnaire Survey

Background: Recent obstetrical practice tends to avoid the use of manual uterine fundal pressure (MUFP);however, data showed that MUFP is actually employed. We here attempted 1) to determine the obstetricians’ attitudes towards MUFP via questionnaire, and 2) to examine whether MUFP shortens the 2nd stage of labor, with the latter tested as a pilot study. Methods: A questionnaire-based study was carried out (n = 122) at meetings of Obstetrics on May 5, 2017. Then, we conducted a pilot case-control study from August 23 to September 6, 2020. Participants (n = 29) were divided into two groups;women who did and did not want MUFP;i.e., MUFP (n = 14) vs. (Non-MUFP) group (n = 15). Results: Of 122 doctors, 99.18% (121/122) used MUFP at cesarean section. 95.90% (117/122) of institutions used MUFP in spontaneous delivery. 95.08% (116/122) obstetricians considered MUFP effective and helpful. 85.24% (104/122) considered that MUFP should be employed after station +3. In the case control study, MUFP vs. Non-MUFP group showed the second-stage-duration of 58.5 (50.25 - 71.25) vs. 48 (39 - 59) minutes, without statistical significance (P = 0.101). However, importantly, MUFP, compared with Non-MUFP group, showed a significantly shorter duration from head visible on introitus (apparition) to delivery;i.e., 21.26 ± 7.32 vs. 30.13 ± 10.61 minutes (P = 0.014). Conclusions: MUFP is still used widely and MUFP shortened the duration of head apparition to delivery time. Larger-sample studies are needed to confirm the efficacy and safety of MUFP.

Application of Sequential Indicator Simulation in Geological Study of X Oilfield in Zhujiangkou Basin

Sequential indicator simulation is a commonly used method for discrete variable simulation in 3D geological modeling and a widely used stochastic simulation method, which can be used not only for continuous variable simulation but also for discrete variable simulation. In this paper, the X Oilfield in the western South China Sea is taken as an example to compare the sequential indicator simulation method and the Indicator Kriging interpolation method. The results of the final comparison show that the results of the lithofacies model established by the Indicator Kriging deterministic interpolation method are overly smooth, and its coincidence rate with the geological statistical results is not high, thus cannot well reflect the heterogeneity of the underground reservoir, while the simulation results of the lithofacies model established by the sequential indicator stochastic simulation method can fit well with the statistical law of the well, which has eliminated the smoothing effect of Kriging interpolation, thus can better reflect the heterogeneity of the underground reservoir. Therefore, the sequential indicator simulation is more suitable for the characterization of sand bodies and the study of reservoir heterogeneity.

蓄热调温羽绒羽毛的制备与性能

以羽绒羽毛纤维(down feather)作为基体,在其表面合成聚多巴胺(PDA)并黏附无机二氧化硅(SiO_(2))为壳材、以正十八烷为有机芯材的相变微胶囊(MEPCM),制备了蓄热调温羽绒羽毛(MEPCM/down feather)。首先利用扫描电子显微镜、粒径分析仪、热重分析仪及防泄漏测试对微胶囊的形貌结构及性能进行了表征,结果表明,制备的微胶囊平均粒径为421.9 nm,且成球性能良好;该微胶囊具有良好的包覆性及形状稳定性。其次,对蓄热调温羽绒羽毛形貌结构及性能进行了测试分析,并考察了MEPCM的添加量对羽绒羽毛性能的影响。结果表明,微胶囊均匀且有效黏附在羽绒羽毛上;当MEPCM的比例为10%,制得的蓄热调温羽绒羽毛熔融温度为26.3℃、熔融热焓为10.9 kJ/kg;且呈现良好的亲水性能、抑菌性能和热管理能力,水洗5次后,熔融热焓仍然能达到8.3 kJ/kg。

Integration of ultrafine CuO nanoparticles with two‐dimensional MOFs for enhanced electrochemicgal CO_(2) reduction to ethylene

To facilitate the electrochemical CO_(2) reduction(ECR)to fuels and valuable chemicals,the development of active,low cost,and selective catalysts is crucial.We report a novel ECR catalyst consisting of CuO nanoparticles with sizes ranging from 1.4 to 3.3 nm anchored on Cu metal‐organic framework(Cu‐MOF)nanosheets obtained through a one‐step facile solvothermal method.The nanocomposites provide multiple sites for efficient ambient ECR,delivering an average C_(2)H_(4) faradaic efficiency(FE)of~50.0%at–1.1 V(referred to the reversible hydrogen electrode)in 0.1 mol/L aqueous KHCO_(3) using a two‐compartment cell,in stark contrast to a C_(2)H_(4) FE of 25.5%and 37.6%over individual CuO and Cu‐MOF respectively,also surpassing most newly reported Cu‐based materials under similar cathodic voltages.The C_(2)H_(4) FE remains at over 45.0%even after 10.0 h of successive polarization.Also,a~7.0 mA cm^(–2) C_(2)H_(4) partial geometric current density and 27.7%half‐cell C_(2)H_(4) power conversion efficiency are achieved.The good electrocatalytic performance can be attributed to the interface between CuO and Cu‐MOF,with accessible metallic moieties and the unique two‐dimensional structure of the Cu‐MOF enhancing the adsorption and activation of CO_(2) molecules.This finding offers a simple avenue to upgrading CO_(2) to value‐added hydrocarbons by rational design of MOF‐based composites.

Exosome-mediated cellular crosstalk within the tumor microenvironment upon irradiation

Radiotherapy is one of the most effective treatment methods for various solid tumors.Bidirectional signal transduction between cancer cells and stromal cells within the irradiated microenvironment is important in cancer development and treatment responsiveness.Exosomes,initially considered as"garbage bins"for unwanted from cells,are now understood to perform a variety of functions in interactions within the tumor microenvironment.Exosome-mediated regulation processes are rebuilt under the irradiation stimuli,because the exosome production,uptake,and contents are markedly modified by irradiation.In turn,irradiation-modified exosomes may modulate the cell response to irradiation through feedback regulation.Here,we review current knowledge and discuss the roles of exosome-mediated interactions between cells under radiotherapy conditions.

How to Select the Best Sensors for TDOA and TDOA/AOA Localization?

This paper focuses on the sensor subset optimization problem in time difference of arrival(TDOA) passive localization scenario. We seek for the best sensor combination by formulating a non-convex optimization problem, which is to minimize the trace of covariance matrix of localization error under the condition that the number of selected sensors is given. The accuracy metric is described by the localization error covariance matrix of classical closed-form solution, which is introduced to convert the TDOA nonlinear equations into pseudo linear equations. The non-convex optimization problem is relaxed to a standard semi-definite program(SDP) and efficiently solved in a short time. In addition, we extend the sensor selection method to a mixed TDOA and angle of arrival(AOA) localization scenario with the presence of sensor position errors. Simulation results validate that the performance of the proposed sensor selection method is very close to the exhaustive search method.

Nonlinear dynamics of fixed-trim reentry vehicles with moving-mass roll control system

Nonlinear dynamic characteristics of a fixed-trim reentry vehicle controlled by an internal moving-mass actuator are analyzed. A traditional dynamic model develops into a five-dimensional nonlinear model using classic Euler angles and their derivatives as state variables. Based on the nonlinear motion equations, by setting the offset distance of the moving-mass as a variation parameter, the curves of the system's equilibrium points are presented by numerical methods. Then the distributions and approximate analytical solutions of the equilibrium points are obtained by simplifying the model under the condition of small intrinsic angles. The results show that the numbers and values of the equilibrium points are closely connected with the location of the moving-mass. Furthermore, the stabilities of equilibrium points are examined by the Lyapunov's first method and three groups of stable equilibrium points are obtained. Since only one group of the stable equilibrium points is desired, the angular motion of the system may be unstable or stay in an undesired lock-in state when the offset distance of the moving-mass or the attitude disturbance of the vehicle is too large. © 2016 Beijing Institute of Aerospace Information.

Time-frequency analysis of Li solid-phase diffusion in spherical active particles under typical discharge modes

Li transient concentration distribution in spherical active material particles can affect the maximum power density and the safe operating regime of the electric vehicles(EVs). On one hand, the quasiexact/exact solution obtained in the time/frequency domain is time-consuming and just as a reference value for approximate solutions;on the other hand, calculation errors and application range of approximate solutions not only rely on approximate algorithms but also on discharge modes. For the purpose to track the transient dynamics for Li solid-phase diffusion in spherical active particles with a tolerable error range and for a wide applicable range, it is necessary to choose optimal approximate algorithms in terms of discharge modes and the nature of active material particles. In this study, approximation methods,such as diffusion length method, polynomial profile approximation method, Padé approximation method,pseudo steady state method, eigenfunction-based Galerkin collocation method, and separation of variables method for solving Li solid-phase diffusion in spherical active particles are compared from calculation fundamentals to algorithm implementation. Furthermore, these approximate solutions are quantitatively compared to the quasi-exact/exact solution in the time/frequency domain under typical discharge modes, i.e., start-up, slow-down, and speed-up. The results obtained from the viewpoint of time-frequency analysis offer a theoretical foundation on how to track Li transient concentration profile in spherical active particles with a high precision and for a wide application range. In turn, optimal solutions of Li solid diffusion equations for spherical active particles can improve the reliability in predicting safe operating regime and estimating maximum power for automotive batteries.

Effect of formulation variables on in vitro release of a water-soluble drug from chitosanesodium alginate matrix tablets

The objective of this study is to investigate the feasibility of using chitosanesodium alginate(CSeSA)based matrix tablets for extended-release of highly water-soluble drugs by changing formulation variables.Using trimetazidine hydrochloride(TH)as a water-soluble model drug,influence of dissolution medium,the amount of CSeSA,the CS:SA ratio,the type of SA,the type and amount of diluents,on in vitro drug release from CSeSA based matrix tablets were studied.Drug release kinetics and release mechanisms were elucidated.In vitro release experiments were conducted in simulated gastric fluid(SGF)followed by simulated intestinal fluid(SIF).Drug release rate decreased with the increase of CSeSA amount.CS:SA ratio had only slight effect on drug release and no influence of SA type on drug release was found.On the other hand,a large amount of water-soluble diluents could modify drug release profiles.It was found that drug release kinetics showed the best fit to Higuchi equation with Fickian diffusion as the main release mechanism.In conclusion,this study demonstrated that it is possible to design extended-release tablets of watersoluble drugs using CSeSA as the matrix by optimizing formulation components,and provide better understanding about drug release from CSeSA matrix tablets.

Evaluation of chitosaneanionic polymers based tablets for extended-release of highly watersoluble drugs

The objective of this study is to develop chitosaneanionic polymers based extendedrelease tablets and test the feasibility of using this system for the sustained release of highly water-soluble drugs with high drug loading.Here,the combination of sodium valproate(VPS)and valproic acid(VPA)were chosen as the model drugs.Anionic polymers studied include xanthan gum(XG),carrageenan(CG),sodium carboxymethyl cellulose(CMC-Na)and sodium alginate(SA).The tablets were prepared by wet granulation method.In vitro drug release was carried out under simulated gastrointestinal condition.Drug release mechanism was studied.Compared with single polymers,chitosaneanionic polymers based system caused a further slowdown of drug release rate.Among them,CS exanthan gum matrix system exhibited the best extended-release behavior and could extend drug release for up to 24 h.Differential scanning calorimetry(DSC)and Fourier transform infrared spectroscopy(FTIR)studies demonstrated that polyelectrolyte complexes(PECs)were formed on the tablet surface,which played an important role on retarding erosion and swelling of the matrix in the later stage.In conclusion,this study demonstrated that it is possible to develop highly water-soluble drugs loaded extendedrelease tablets using chitosaneanionic polymers based system.

Geomechanics involved in gas hydrate recovery

Gas hydrate is regarded as a promising energy owing to the large carbon reserve and high energy density.However,due to the particularity of the formation and the complexity of exploitation process,the commercial exploitation of gas hydrate has not been realized.This paper reviews the physical properties of gas hydratebearing sediments and focuses on the geomechanical response during the exploitation.The exploitation of gas hydrate is a strong thermal–hydrological–mechanical–chemical(THMC)coupling process:decomposition of hydrate into water and gas produces multi-physical processes including heat transfer,multi-fluid flow and deformation in the reservoir.These physical processes lead to a potential of geomechanical issues during the production process.Frequent occurrence of sand production is the major limitation of the commercial exploitation of gas hydrate.The potential landslide and subsidence will lead to the cessation of the production and even serious accidents.Preliminary researches have been conducted to investigate the geomechanical properties of gas hydrate-bearing sediments and to assess the wellbore integrity during the exploitation.The physical properties of hydrate have been fully studied,and some models have been established to describe the physical processes during the exploitation of gas hydrate.But the reproduction of actual conditions of hydrate reservoir in the laboratory is still a huge challenge,which will inevitably lead to a bias of experiment.In addition,because of the effect of microscopic mechanisms in porous media,the coupling mechanism of the existing models should be further investigated.Great efforts,however,are still required for a comprehensive understanding of this strong coupling process that is extremely different from the geomechanics involved in the conventional reservoirs.